Abstract: Using the experiment method of tuber culture in the laboratory,the photosynthesis effects and physiological response of the aquatic macrophyte Potamogeton pectinatus were investigated in Pb²⁺with different concentrations. The results showed that thePotamogeton pectinatus growth was inhibited with the increase of the concentration, chlorophyll content reduced significantly and showed negative correlation with Pb²⁺ concentrations, RuBPc activity first increased and then decreased,and it  was negatively correlated with Pb²⁺ concentrations, PEPc activity changed little, CA activity first decreased and then increased.